BPA and its manufacture is described U.S. Pat. No. 4,950,805 (Iimuro et al.); U.S. Pat. No. 5,345,000 (Moriya et al.); and U.S. Pat. No. 6,806,394 (Evitt et al.), which patents are incorporated herein by reference.
BPA is produced commercially by the condensation of acetone and phenol over an acid catalyst and, in fact, BPA production is the largest consumer of phenol. Currently, the most common route for the production of phenol comprises a four-step process in which the first step involves alkylation of benzene with propylene to produce cumene, followed by oxidation of the cumene to the corresponding hydroperoxide, followed by cleavage of the hydroperoxide to produce equimolar amounts of phenol and acetone, as well as other reaction byproducts, and then a series of steps to separate and purify acetone and phenol from each other and from unwanted reaction byproducts which produces a waste stream comprising water, unrecovered phenol, unrecovered acetone, and other reaction byproducts.
The production of BPA consumes two moles of phenol and one mole of acetone to produce one mole of BPA and one mole of water. In subsequent process steps, the water is removed from the process and the BPA is purified. According to the present disclosure, an integrated process in which part of the required phenol is produced from cumene, and part is produced by an efficient integration of phenol recovery from the aqueous waste streams from the phenol/acetone production process, e.g., hydroperoxide cleavage, and BPA production process, the overall process is improved economically and environmental friendly. The phenol recovered from the aqueous waste streams from, for example, the series of steps to separate and purify phenol and acetone in the crude product stream from the hydroperoxide cleavage step and from the BPA production step is purified and recycled for use in the reaction with acetone to reduce the overall consumption of phenol in the production of BPA.
Various procedures are taught for removing phenol from process waste streams. U.S. Pat. No. 3,963,610 describes a process for removing phenol from waste water that occurs in the manufacture of phenol by the cumene process using cumene as extractant. U.S. Pat. No. 6,071,409 similarly describes an extraction process using a tertiary amyl ether extractant to remove phenol. U.S. Pat. No. 5,344,528 describes a process for removing phenol by distillation from the waste water stream from a phenol plant with an objective of removing as much of the phenol as possible before sending the stream to a biological waste treatment facility. U.S. Pat. No. 6,824,687 describes a process suitable for phenol removal from waste water from a phenol/acetone plant.
European Pat. No. 0758636 B1 describes a two-step process for removing phenol and other educts and products from a BPA process waste water stream using a counter-current extraction process with an organic solvent followed by passing raffinate through an adsorption unit filled with polystyrene resin. U.S. Pat. No. 6,972,345 B2 describes a process for extracting phenol from waste water from a BPA process using a mixed solvent extractant of methyl isobutyl ketone, anisole and, optionally, mesitylene.